Water-cooling apparatus and method



Aug. 15, 1939. A. F. EVERS, JR 2,169,795

I WATER-COOLING APPARATUS AND METHOD Filed Jan. 28, 1959 2 Shaets-Sheet 1 INVENTOR- 'A; F. EVERS. JR

WATER-COOLING APPARATUS AND METHOD Filed Jan. 28, 1939 2 Sheets-Sheet 2 m n I n n u n I I n I 'IIIIIIIIIIIIIIIIIIIIIIIIII n n v INVENTOR.

Patented Aug. 15, 1939 UNITED STATES PATENT WATER-COOLING APPARATUS AND METHOD 9 Claims.

This application is a continuation in part of application No. 172,066. It is the latest addition in a sequence in which Patent No. 1,994,698 forms the first part and all the amendments to application No. 172,066 form the second part.

My invention relates to new and useful improvements in water cooling apparatus and methods and it consists in the combinations, constructions and arrangements hereinafter described.

An object of my invention is to provide a twotemperature household refrigerator capable of cooling water in warm climates yet retaining practically all of the good features found) in present day simple refrigerators.

Other objects and advantages will appear in the following specification and the novel features of the invention will be particularly pointed out in the appended claims.-

My invention is illustrated in the accompanying drawings forming part of this application in which:

Figure 1 is a diagrammatic representation of a circulating refrigeration system embodying the present invention illustrating two evaporators in the system and connected in series arrangement.

Figure 2 is a diagrammatic showing of a second form of the invention.

Figure 3 illustrates a conventional household refrigerator which has been modified to include the present invention.

The structure of my invention includes a cabinet I within which is disposed the high side or condensing unit 2, the evaporators 3 and 4 and the connecting lines'and controls.

The liquid line H connects the high side 2 to the thermostatic expansion valve 5 which in turn connects to the inlet of the main evaporator 3. The outlet of the evaporator 3 through tubing 25 connects to the inlet of the secondary evaporator 4. The outlet of evaporator 4 connects to the suction line l2 which in turn leads back to the high side 2, thereby completing the refrigerants circuit. It will be noted that the two evaporators are connected in series.

5 is a thermostatic expansion valve with capillary tubing I 5 and sensitive bulb 9. The. bulb 9 lies in controlling relation to'the evaporator 3. Wire 20 connects to the thermostatic switches 6 and I which control theevaporators 3 and 4, respectively. 21 is the actuating bellows of switch 6 and is connected to the bulb l3 while bellows 26, connected to bulb l4, controls the operation of switch I. The switches 6 evaporator 3, the connector 25 and I control the supply of current individually to the motor ,on the high side 2. The electric heater 8 lies in close thermal contact with the bulb 9 and is connected in'series relation with the switch I. 5

The heater 8 may contain either a slow heating plain element or a fast heating thermostatically controlled element, Fig. 2 illustrating the former and Fig. 1 the latter. The evaporator 4 is surroundedby water contained in the tank I9 10 which has two ports 16 and I l. The two ports are provided for outside water connections including a faucet 'not shown for drinking water.

It may also be said of Figs. 1 and 2 that the and the evaporator 4 form one single evaporator comprising first and second sections.

In Fig. 1 the pressure actuated switch 28 operates as an individual control to the heater 8.

Here the switch 1, the heater 8 and the switch 20 28 are connected in series relation. "As may be observed the bellows 29, the spring 30 and the adjusting nut 3| are parts of the switch 28.

Operation-Figure 1 tively the evaporator 3, the connector 25, the

evaporator 4 and the suction line .l2 back to the high side 2 thereby completing the circuit. Control of the valve 5 lies in the bulb 9. The pressure switch 28, which is sensitive to small changes in temperature, is adjusted to open at that back pressure which, when held constant, will insure the proper back pressure in the vapor discharged 40 from evaporator 4 when the latter is operating to cool the water in tank l9.

In the present instance the correct constant back pressure value is one which terminates the operating cycle of the evaporator 4' simulaneously with the attainment of a low superheat value of 10 degrees F. within same. The pressure switch 28 operating through the heater 8, the bulb 9 and the valve 5 holds the back pressure at this practically constant set value. This constant pressure value is somewhat higher than the highest valuegof the range of pressures prevailing in evapo tor 3 when the latter alone is producing refrigeration.

frigeration is to take place the bulb controls l3 and I4 cause the switches 3 and I respectively to be closed. Current from the mains flows through line 23, through switch 6, through line 2 I, through the motor on the high side 2 and returns via line 24. Also it flows through line 20, through switch I, through line 22, through heater 8, through line 23, through switch 28 and returns via line 24.

The switch I, being adjusted for cold drinking water, opens when the temperature of the bulb i4 drops to 33 degrees F. Up to this point the heater 8, under rigid control of the switch 28, has been in operation. Also the valve 5 has, in effect, been acting as a simple pressure reducing valve. With sulphur dioxide as the refrigerant, the back pressure has been constantly at a value approximating 3 pounds. The temperature of the boiling refrigerant inside the evaporator 3, the connector 25 and the evaporator 4 has constantly been approximately 23 degrees F. in value. The terminus of the boiling refrigerant, which at the beginning of the operating cycle was some point between the'beginning and end of the evaporator 4, has progressively extended through the evaporator and is now at the outer end.

The superheat, which at the beginning of the cycle was comparatively high, has, at the end of the evaporator 4s cycle, dropped to a value of 10 degrees within same.

Upon completion of the evaporator .4s operating cycle and upon opening of the switch the heater 3 cools. The bulb 9 is now cooled by the surface temperature of the evaporator 3 which is close to that of the boiling refrigerant inside, or 23 degrees F. The bulb control 9 now takes active charge of the valve 5, maintaining a constant superheat of approximately 10 degrees in the evaporator 3 individually. Simultaneously the boiling refrigerant frostline or terminus is retracted until it extends to a point in the evaporator 3 just above the bulb 9, the valve 5 now' functioning as a simple thermostatic expansion valve.

The mean temperature of the evaporator 3 is' set at 2,0 degrees F. while that of the evaporator 4 is set at 40 degrees. With control of the valve 5 now lying in the bulb 9 refrigeration continues in the evaporator 3 alone until its temperature decreases agiven additional amount whereby the cooled bulb control 13 causes the switch 6 to open, stopping operation of the condensing unitand ending the cycle.

Ordinarily the water, being thermally inside the refrigerator, remains cold for indefinite periods. With the water cold the evaporator 4 together with its controls retires from active participation in the systems functioning, acting merely as a passageway for refrigerant, and the refrigerator becomes, in effect, a simple one with all of the advantages of the same.

Ordinarily the evaporator 4 will operate only infrequently and for comparatively short periods of time. During these operating periods the superheat of the refrigerant in the evaporator 3 remains at an approximate zero value and the temperature at an approximate value of 23 degrees F.

The refrigeration system illustrated in Fig. 1 comprises essentially a simple refrigerator, a part of whose suction line may operate as a second v evaporator, and in which the heat controlled expansion valve is, upon demand, subjected to a measured amount of heat superimposed upon its sensitive bulb, which action both extends the evaporator section and alters the evaporator operation from that of constant -superheat to I The refrigeration system illustrated in Fig. 2 is, generally,-the same as that shown in Fig. 1. In Fig. 2 the pressure switch 28 is eliminated and its function, that of controlling the heat which actuates the thermostatic expansion valve 5 when the evaporator ,4 is being refrigerated, is performed by valve 5 and the controls therefor. These controls are filled at the factory with a volatile liquid in the power element which is so proportioned as to conform with the several requirements of this invention. A volatile liquid charge is used which will become totally saturated vapor at a temperature of 33 degrees F. which is the correct temperature in this instance. Under the influence of these controls, so charged, the evaporator 3 operates indvidually under constant superheat and remains constantly at a temperature lower than freezing, while the evaporator 4 operates under a constant back pressure and terminates its cycle with 10 degrees of superheat.

In the arrangement shown in Fig. 1 the heat which is superimposed upon the bulb 3 never exceeds an actual value of 33 degrees. In Fig. 2 the heat which is superimposed upon the bulb 9.

though actually above, never exceeds an effectivevalue of 33 degrees.

When the evaporator 4 is undergoing refrigeration the evaporator 3 is undergoing sufflcient refrigeration to maintain a coating of frost upon same.

The reason the sensitive bulb operates as though it remained at an effective temperature of 33 degrees regardless of an actual higher temperature is to be found in the natural characteristics of the volatile fluid with which the valve 5 is gascharged. If the controls for the valve 5 be charged with saturated vapor at a given temperature, 33 degrees in the present instance, then at all higher temperatures the pressure of this vapor will operate to remain in a substantially static condition while at all lower I temperatures it will operate to decrease in value as the bulbs temperature drops. This odd performance is due directly to the fact that the sensitive bulb is of small volume and at all temperatures lower than that of charging there is more or less volatile liquid in the sensitive bulb and its pressure-temperature characteristics obey the laws of boiling liquids. While at all temperatures higher than that of charging there is only unsaturated vapor or gas within the entire power element and the pressure-temperature characteristics then obey the laws of gases. 1

Also it may be remarked here that the valve 5, to produce the results described in this specification, must be charged in a conventional manner insofar as the type of charging liquid is concerned. In other words the volatile liquid which comprises the fluid charge within the power element must have the same pressure-temperature characteristics as those of the refrigerant which the valve controls.

I claim:

1. Refrigerating apparatus comprising an evaporator, a condensing means for supplying liquid refrigerant thereto and for withdrawing vaporized refrigerant therefrom, and means for controlling theflow of refrigerant through the evaporator, saidevaporator comprising a first sectionand a second section in series therewith;

and said control means comprising an expansion valve at the inlet of said evaporator, a thermostaticdevice controlling the operation of said valve and means for modifying the eifect of said device; said device comprising an end portion responsive to the superheat of the vaporized refrigerant in the first evaporator section, said device enclosing a. volatile fluid therein, said volatile fluid having pressure-temperature characteristics which are substantially the same as the pressure-temperature characteristics of the refrigerant controlled thereby, the pressure of said volatile fluid tending to open said valve, thepressure of the refrigerant in the evaporator,

tending to close said valve, said modifying means comprising a thermostat responsive to temperature changes in the second evaporator section and means actuated by said thermostat for superimposing a definite amount of heat upon said end portion of said device. sa d heat being so proportioned in quantity as to effect a constant operating pressure-in said second evaporator section.

a thermostat responsive to temperature changes in the first evaporator section and means for effecting individual operating control of said condensing means by each, thermostat.

2. Refrigerating apparatus comprising an evap- I orator, a condensing means for supplying liquid refrigerant thereto and for withdrawing vaporized refrigerant therefrom, and means for controlling the flow of refrigerant through the evaporator, said evaporator. comprising a first section and a second section in series therewith; and said control means comprising an expansion valve at the inlet of said evaporator, a thermostatic device controlling the operation of said valve and means for modifying the effect of said device;

said device comprising -an end portion responsive to the-superheat of the vaporized refrigerant in thefirst evaporator section. said device enclosing a volatile fluid therein, said volatile fluid having pressure-temperature characteristics which are substantially" the same as the pressure-temperature characteristics of the refrigerant controlled thereby, said volatile fluid being so proportioned in quantity that its maximum possible pressure under the influence of heat is correct for effecting a constant operating pressure in the second evaporator section, the pressure of said volatile fluid tending to open said valve, the pressure of l the refrigerant'in the evaporator tending to close said valve, said modifying means comprising a thermostat responsive to temperature changes in the second evaporator section and means actuated by said thermostatfor superimposing heat upon said end portion or said device, a thermostat responsive to temperature changes in the first evaporator section and means for effecting individual operating control of said condensing means by each thermostat.

3. Refrigerating apparatus comprising an evaporator, a condensing means for supplyingliquid refrigerant thereto and for withdrawing vapor- .ized refrigerant therefrom, and means for controlling the flow of refrigerant through theevaporator, said evaporator comprising a first section and a second section in series therewith; and

said control means comprising an expansion valve at the inlet of said evaporator, .a thermostatic device controlling the operation of said valve and means for modifying the effect of said device;

said device comprising an end portion responsive to thesuperheat of the vaporized refrigerant in the first evaporator section, said device enclosing a volatile fluidtherein, said volatile fluid having thereby, the pressure of said volatile fluid tending to open said valve, the pressure of the refrigerant in the evaporator tending to close said valve, said modifying means comprising a thermostat responsive to temperature changes in the second evaporator section and means actuated by said thermostat for superimposing a definite amount of heat upon said end portion of said device, said heat superimposing meansfcomprising an electric heater controlled by a pressure actuated switch, said switch being actuated by the pressure in the evaporator, said heat being applied intermittently in quantities suflicient to constantly maintain said end portion of said device at that temperature which is the same as the ultimate mean low temperature of the medium undergoing refrigeration by the second evaporator section, a thermostat responsive to changes in the first evaporator section and means for effecting individual operating control of said condensing means by each thermostat with said thermostat belonging to said second evaporator section taking preference under joint operating control.

4. Refrigerating apparatus comprising an evaporator, a condensing means for supplying liquid refrigerant thereto and for withdrawing evaporator, said evaporator comprising a first section and a second section in series therewith; and said control means comprising an expansion valve at the inlet of said evaporator, a thermostatic device controlling the operation of said valve and means for modifying the effect of said device; said device comprising an end portion responsive to the superheat of the vaporized refrigerant in the first evaporator section, said device enclosing a volatile fluid therein, said volatile fluid having pressure-temperature characteristics which are substantially the same as the pressure-temperature characteristics of the refrigerant controlled thereby, said volatile fluid being so proportioned in quantity that its condition of complete, saturated vaporization will occur at that temperature which is the same as the ultimate mean low temperature of the medium undergoing refrigeration by the second evaporator section, the pressure of said volatile fluid tending to open said valve, the pressure of the refrigerant in the evaporator tending to close said valve, said modifying means comprising a thermostat responsive to temperature changes in the second evaporator section and means actuated by said thermostat for superimposing heat- 5. The method of producing refrigeration by means of a system including an evaporator made up of a pair of sections connected in series; said method comprising the steps of admitting refrigerantto the evaporator and limiting the quantity admitted, when refrigeration-is demanded of the first section only, to an amount required to produce a constant superheat in the said first section by regulating the flow through a control device including a thermostatic element subjected to the temperature of the end of the first evaporator section, and controlling the flow, when refrigeration is required of the second section or both sections, by subjecting said thermostatic element to a predetermined constant quantity of heat from a device controlled by the temperature of the matter to be cooled by the second section.

6. The method of refrigeration which comprises circulating refrigerant serially through a primary and a secondary evaporator and confining the evaporation to the primary evaporator, when cooling is not demanded of the second evaporator, by admitting the correct amount of liquid refrigerant to the primary evaporator to maintain a predetermined superheat in the refrigerant discharged therefrom through the regulating effect of the back pressure of refrigerant in the primary evaporator and an opposing pressure developed from the temperature at the end of said primary evaporator, and, when refrigeration is required of both evaporators or the secondary evaporator only, supplying liquid refrigerant to the evaporators in a quantity regulated by counterbalancing the back pressure of the refrigerant in the evaporators by a pressure developed from a flow of heat at constant predetermined temperature from a source under control of the matter to be cooled by the second evaporator.

7. Refrigerating apparatus comprising an evaporator, a condensing means for supplying liquid refrigerant thereto and for withdrawing vaporized refrigerant therefrom, and means for controlling the flow of refrigerant through the evaporator, said evaporator comprising a first section and a second section in series therewith; and said control means comprising an expansion valve at the inlet of said evaporator, a thermostatic device controiling the operation. of said valve and means for modifying the effect of said device; said device comprising a tube extending from said valve and terminating in an end memher in thermal engagement with the outlet of the first evaporator section; said modifying means including an electric heating element arranged to heat said end member to a predetermined temperature and a control circuit for supplying current to said heating member, said circuit including a switch device and a thermostat for controlling said switch and arranged to be affected by changes in the temperature of the medium to be cooled by the second evaporator section.

8. A structure such-as is defined in claim 7, in which said control circuit includes a switch operated by the suction pressure in the discharge line from the evaporators and arranged in series with said switch device.

9. A structure such as is defined in claim 7 which includes a tank for holding a supply of ,water and housing said second evaporator section and in which the thermostat for controlling saidgswitch device is positioned in contact with said tank.

- ADOLPH F. EVERS, Jn. 

